JPH0825991B2 - Method for producing dithiol di (meth) acrylate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing dithiol di (meth) acrylate useful as a raw material for an acrylic resin or a methacrylic resin.

[Conventional technology]

Ethylene glycol diacrylate, diethylene glycol dimethacrylate, and (meth) acrylate of ethylene oxide adduct of bisphenol A have been used for modification, that is, crosslinking of polymethacrylate resin.

[Problems to be Solved by the Invention] The present inventors have studied the use of acrylic resins and methacrylic resins as resins for optical parts such as lenses. When using acrylate, diethylene glycol dimethacrylate, and (meth) acrylate of ethylene oxide adduct of bisphenol A, a high refractive index cannot be expected.

Therefore, the present inventors have previously described the general formula (II) (In the formula, A represents oxygen or sulfur, R represents hydrogen or a methyl group, m is 1 or 2, and n is an integer of 0 or 1.) A resin obtained by radical polymerization is highly advanced. It was discovered that it has a refractive index of, and it was proposed to use it as a resin for optical parts. (JP-A-63-188
660) These compounds can be synthesized by a conventionally known method in which a dithiol raw material is reacted with acrylic acid chloride or methacrylic acid chloride. However,
In these methods, the reaction of addition of dithiol to the olefin group of acrylic acid chloride or methacrylic acid chloride as a by-product proceeds, so that not only the yield is inferior, but also the purification method becomes difficult, and the inclusion of these by-products. There is a problem that the above-mentioned monomer is likely to cause coloration when polymerized.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present inventors have replaced the industrially expensive acrylic acid chloride or methacrylic acid chloride used as a raw material with a cheaper β-chloropropionyl chloride or β-chloro-α. The inventors have made earnest studies on a method for producing a dithiol di (meth) acrylate represented by the general formula (II) using methylpropionyl chloride as a raw material.

As a result, even when β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride is used as a raw material, the esterification reaction and dehydrochlorination can be performed by adopting the selected hydrochloric acid scavenger and the specified reaction conditions. The inventors have found that not only can the (olefination) reaction be carried out in the same reaction system, but also the addition reaction of dithiol to olefin can be avoided, and the present invention has been completed.

That is, the present invention comprises a dithiol represented by the general formula (I) in a polar organic solvent at a temperature of −10 to 40 ° C. in the presence of 1.5 to 3.0 mol of caustic soda or an aqueous caustic potash solution per mol of 1.5 to 3.0 mol. Of β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride of the formula (I) at a temperature of −10 to 40 ° C.
The dithiol di (meth) represented by the general formula (II) is obtained by reacting 1.5 to 3.0 mol of caustic soda, caustic potash aqueous solution or tertiary amine with 1 mol of dithiol represented by
It is a method for producing an acrylate.

As the polar organic solvent used in the method of the present invention, any organic solvent capable of dissolving the dithiol represented by the general formula (I) and having good compatibility with water can be used, but preferably acetone, methyl ethyl ketone, etc. Ketones, N, N-dimethylformamide, dimethylsulfoxide and the like are used. The amount of these polar organic solvents used is 1 to 30 times by weight that of the dithiol represented by the general formula (I).

The concentration of the caustic soda or caustic potash aqueous solution used in the esterification reaction is not limited, but 50% by weight or less, which is stable as an aqueous solution, is preferable, and the amount of caustic soda or caustic potash used is represented by the general formula (I). The molar ratio is 1.5 to 3.0 with respect to dithiol. When the content of caustic soda or potassium hydroxide is less than 1.5, the hydrolysis reaction of unreacted β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride is likely to occur. Along with this, during the olefination reaction, oxidation of the unreacted dithiol represented by the general formula (I) and addition reaction between the unreacted dithiol represented by the general formula (I) and the produced dithiol di (meth) acrylate are likely to occur. Therefore, the yield of the dithiol di (meth) acrylate represented by the general formula (II) decreases. On the other hand, even when the molar ratio exceeds 3.0, the hydrolysis reaction of β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride easily occurs, and the yield of dithiol di (meth) acrylate represented by the general formula (II) is increased. The rate drops.

The amount of β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride used is 1.5 with respect to the dithiol represented by the general formula (I).
~ 3.0 molar ratio. When β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride is less than 1.5 mol ratio, the unreacted dithiol represented by the general formula (I) reacts with the dithiol di (meth) acrylate produced during the olefination reaction. Then, the yield of the dithiol di (meth) acrylate represented by the general formula (II) decreases. If the molar ratio exceeds 3.0, the residual β
-Chloropropionyl chloride or β-chloro-α
-Methyl propionyl chloride causes an irritating odor, and dithiol di (meth) represented by the general formula (II) of the crude product
The acrylate purification process becomes complicated.

Next, the concentration of the caustic soda or caustic potash solution used in the olefination reaction is not limited as in the esterification reaction, but 50% by weight or less, which is stable as an aqueous solution, is preferable, and the amount of caustic soda or caustic potash used is The molar ratio is 1.5 to 3.0 with respect to the dithiol represented by the general formula (I). Further, as the tertiary amine used in the present invention, trimethylamine, treethylamine, triethylenediamine and the like can be mentioned. In the case of using these, the amount used is 1.5 mol relative to the dithiol represented by the general formula (I). ~ 3.0 molar ratio. When caustic soda, caustic potash, or a tertiary amine is less than 1.5 mol ratio, the olefination reaction is not completed, and it becomes difficult to take out highly pure dithiol di (meth) acrylate represented by the general formula (II). On the other hand, when the content of caustic soda or potassium hydroxide exceeds 3.0, the hydrolysis reaction of the dithiol di (meth) acrylate represented by the general formula (II) becomes vigorous. On the other hand, if the tertiary amine exceeds 3.0 mole ratio, it not only causes a pungent odor to remain in the dithiol di (meth) acrylate represented by the general formula (II), but also tends to cause coloring of the product.

Next, the reaction temperature in the method of the present invention is −10 to 40 ° C., particularly preferably 0 to 10 ° C. for both the esterification reaction and the olefination reaction. If it is too low, the esterification from the dithiol represented by the general formula (I) and the olefination reaction after the esterification reaction are difficult to proceed, and if it is too high, β-chloropropionyl chloride or β-chloro-α-methyl is used in the esterification reaction. The hydrolysis reaction of propionyl chloride and the produced ester is likely to occur, and the hydrolysis reaction of the dithiol di (meth) acrylate represented by the general formula (II) is likely to occur in the olefination reaction, resulting in a decrease in yield.

Thus, as a general embodiment of the method of the present invention,
A dithiol represented by the general formula (I) is dissolved in a polar organic solvent, stirred, and cooled to an internal temperature of −10 to 40 ° C., and the dithiol represented by the general formula (I) 1
After adding 1.5-3.0 mol of caustic soda or caustic potash aqueous solution to the total amount of mol, 1.5-3.0 mol of β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride is added dropwise from the dropping funnel over 1 to 8 hours. Then, 1.5 to 3.0 mol of caustic soda or caustic potash solution or tertiary amine is added dropwise over 1 to 8 hours, or 1.5 to 3.0 mol of caustic soda or potash solution and 1.5 to 3.0 mol of β-chloropropionyl chloride or β. -Chloro-α-methylpropionyl chloride is added dropwise from separate dropping funnels simultaneously over 1-8 hours, and 1.5-3.0 mol of caustic soda or potassium hydroxide solution or tertiary amine is added dropwise over 1-8 hours. And a dithiol di (meth) acryle represented by the general formula (II) by such a method. It can be produced the door in a high yield. After completion of the reaction, water is added to the reaction solution to perform extraction using hydrocarbons, particularly n-hexane as an extraction solvent, to obtain the desired dithiol di (meth) acrylate represented by the general formula (II) with high purity and high purity. It can be obtained in yield.

[Action and effect]

According to the present invention, the dithiol represented by the general formula (I) is esterified by reacting β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride in a polar organic solvent in the presence of caustic soda or aqueous caustic potash solution. Then, the esterification and the olefination can be carried out in the same reaction system by contacting with caustic soda, an aqueous solution of caustic caustic or a tertiary amine to carry out an olefination reaction, and the dithioldi ( Advantageously, meth) acrylates can be obtained.

The β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride used in this method is an industrially easily available raw material, and the method of the present invention is economically and technically excellent and industrially significant. It is a manufacturing method. The method of the present invention can also be used as a method for producing other thiol (meth) acrylates.

〔Example〕

Next, the present invention will be described in detail with reference to examples, but all parts shown in the examples are parts by weight.

Example 1 2,3'-oxydiethanethiol 13.5 in 200 parts of acetone
Part (0.10 mol) was dissolved, and 39.0 parts (0.20 mol) of 20 wt% aqueous sodium hydroxide solution was added with stirring. At this time, the content liquid was cooled to keep it at 10 ° C.

Next, 25.0 parts (0.20 mol) of β-chloropropionyl chloride was added dropwise over 2 hours while keeping the content liquid at 10 ° C. After the dropping, 21.6 parts (0.22 mol) of triethylamine was added dropwise over 2 hours while keeping the content liquid at 10 ° C.

After completion of the reaction, 500 parts of water and 250 parts of n-hexane were added while continuing stirring. Then, the n-hexane solution layer was separated and concentrated. After 250 parts of n-hexane was added to the concentrated solution to dissolve it, the concentrate was washed with 300 parts of water and decolorized with 6 parts of activated carbon. Then, the n-hexane solution was concentrated to obtain 21.7 parts of colorless syrup-like 2,2'-oxydiethanethiol diacrylate.

According to analysis by liquid chromatography, the purity was 99%, and the yield based on 2,2'-oxydiethanethiol was 87 mol%.

 The elemental analysis values were as follows.

Elemental analysis value (%) C H S analysis value 48.60 5.91 5.84 calculated value 48.76 6.03 26.03 Example 2 2,2′-thiodiethanethiol 15.4 parts (0.10 mol) was dissolved in 120 parts of N, N-dimethylformamide, While stirring, the entire amount of 41.1 parts (0.22 mol) of a 30 wt% potassium hydroxide aqueous solution was added. At this time, the content liquid was cooled to keep it at 20 ° C.

Next, 28.2 parts (0.20 mol) of β-chloro-α-methylpropionyl chloride was added dropwise over 2 hours while keeping the content liquid at 20 ° C. After dropping, keep the content liquid at 20 ℃.
41.1 parts (0.22 mol) of a 30 wt% potassium hydroxide aqueous solution was added dropwise over 2 hours.

After completion of the reaction, 500 parts of water and 250 parts of n-hexane were added while continuing stirring. Then, the n-hexane solution layer was separated and concentrated. After 250 parts of n-hexane was added to the concentrated solution to dissolve it, the concentrate was washed with 300 parts of water and decolorized with 6 parts of activated carbon. Then, the n-hexane solution was concentrated to obtain 24.0 parts of colorless syrup-like 2,2'-thiodiethanethiol dimethacrylate.

According to analysis by liquid chromatography, the purity was 98%, and the yield based on 2,2'-thiodiethanethiol was 81 mol%.

 The elemental analysis values were as follows.

Elemental analysis value (%) C H S analysis value 49.51 6.13 33.20 calculated value 49.62 6.25 33.12 Example 3 150 parts of acetone and 12.3 parts of 1,4-butanedithiol (0.10)
Mol), and while stirring the mixture to maintain the contents at 15 ° C, β-chloro-α-methylpropionyl chloride 27.5
Parts (0.22 mol) and 30 wt% caustic soda aqueous solution 29.3 parts (0.
(22 mol) were placed in separate dropping funnels and simultaneously added dropwise over 2 hours. After the dropping was completed, 21.6 parts of triethylamine (0.22
Mol) was added dropwise over 2 hours.

After completion of the reaction, 500 parts of water and 250 parts of n-hexane were added while continuing stirring. Then, the n-hexane solution layer was separated and concentrated. After 250 parts of n-hexane was added to the concentrated solution to dissolve it, the concentrate was washed with 300 parts of water and decolorized with 6 parts of activated carbon. Next, the n-hexane solution is concentrated to give colorless syrupy 1,4-butanedithiol diacrylate 19.
I got 5 copies.

Analysis by liquid chromatography shows a purity of 98% and a yield based on 1,4-butanedithiol of 85%.
It was mol%.

 The elemental analysis values were as follows.

Elemental analysis value (%) C H S analysis value 51.97 6.22 27.69 Calculated value 52.14 6.13 27.84

Claims (1)

[Claims] 1. General formula (I) HS (CH ₂ ) _m A _n (CH ₂ ) _m SH (I) (wherein A represents oxygen or sulfur, m is 1 or 2,
n is an integer of 0 or 1. ) Dithiol represented by in a polar organic solvent, -10 ℃ ~ 40 ℃
In the presence of 1.5 to 3.0 mol of caustic soda or aqueous caustic potash solution per 1 mol at a temperature of 1.5 to 3.0 mol of β-chloropropionyl chloride or β-chloro-α-methylpropionyl chloride, and further -10 to
At a temperature of 40 ° C., 1 to 1 mol of the dithiol represented by the general formula (I) is reacted with 1.5 to 3.0 mol of caustic soda, an aqueous caustic potash solution or a tertiary amine, which is characterized by the general formula (II). (In formula, A shows oxygen or sulfur, R shows hydrogen or a methyl group, m is 1 or 2, n is an integer of 0 or 1.) The manufacturing method of the dithiol di (meth) acrylate represented by these.